cmd/compile: change Func.FCurfn to IsHiddenClosure

IsHiddenClosure is more descriptive.

Change-Id: I06651072925a958b148b64ab0db3a9bfc839af9b
Reviewed-on: https://go-review.googlesource.com/32224
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

src/cmd/compile/internal/gc/dcl.go

@@ -347,7 +347,7 @@ func newname(s *Sym) *Node {
 func newfuncname(s *Sym) *Node {
 	n := newname(s)
 	n.Func = new(Func)
-	n.Func.FCurfn = Curfn
+	n.Func.IsHiddenClosure = Curfn != nil
 	return n
 }
 

src/cmd/compile/internal/gc/esc.go

@@ -18,7 +18,7 @@ import (
 // The algorithm (known as Tarjan's algorithm) for doing that is taken from
 // Sedgewick, Algorithms, Second Edition, p. 482, with two adaptations.
 //
-// First, a hidden closure function (n.Func.FCurfn != nil) cannot be the
+// First, a hidden closure function (n.Func.IsHiddenClosure) cannot be the
 // root of a connected component. Refusing to use it as a root
 // forces it into the component of the function in which it appears.
 // This is more convenient for escape analysis.
@@ -58,7 +58,7 @@ func visitBottomUp(list []*Node, analyze func(list []*Node, recursive bool)) {
 	v.analyze = analyze
 	v.nodeID = make(map[*Node]uint32)
 	for _, n := range list {
-		if n.Op == ODCLFUNC && n.Func.FCurfn == nil {
+		if n.Op == ODCLFUNC && !n.Func.IsHiddenClosure {
 			v.visit(n)
 		}
 	}
@@ -78,7 +78,7 @@ func (v *bottomUpVisitor) visit(n *Node) uint32 {
 
 	v.stack = append(v.stack, n)
 	min = v.visitcodelist(n.Nbody, min)
-	if (min == id || min == id+1) && n.Func.FCurfn == nil {
+	if (min == id || min == id+1) && !n.Func.IsHiddenClosure {
 		// This node is the root of a strongly connected component.
 
 		// The original min passed to visitcodelist was v.nodeID[n]+1.

src/cmd/compile/internal/gc/sizeof_test.go

@@ -22,7 +22,7 @@ func TestSizeof(t *testing.T) {
 		_32bit uintptr     // size on 32bit platforms
 		_64bit uintptr     // size on 64bit platforms
 	}{
-		{Func{}, 96, 168},
+		{Func{}, 92, 160},
 		{Name{}, 52, 80},
 		{Node{}, 92, 144},
 		{Sym{}, 60, 112},

src/cmd/compile/internal/gc/subr.go

@@ -361,7 +361,7 @@ func nod(op Op, nleft *Node, nright *Node) *Node {
 	switch op {
 	case OCLOSURE, ODCLFUNC:
 		n.Func = new(Func)
-		n.Func.FCurfn = Curfn
+		n.Func.IsHiddenClosure = Curfn != nil
 	case ONAME:
 		n.Name = new(Name)
 		n.Name.Param = new(Param)

src/cmd/compile/internal/gc/syntax.go

@@ -284,7 +284,6 @@ type Func struct {
 	Ntype      *Node // signature
 	Top        int   // top context (Ecall, Eproc, etc)
 	Closure    *Node // OCLOSURE <-> ODCLFUNC
-	FCurfn     *Node
 	Nname      *Node
 
 	Inl     Nodes // copy of the body for use in inlining
@@ -296,11 +295,12 @@ type Func struct {
 	Endlineno int32
 	WBLineno  int32 // line number of first write barrier
 
-	Pragma        Pragma // go:xxx function annotations
-	Dupok         bool   // duplicate definitions ok
-	Wrapper       bool   // is method wrapper
-	Needctxt      bool   // function uses context register (has closure variables)
-	ReflectMethod bool   // function calls reflect.Type.Method or MethodByName
+	Pragma          Pragma // go:xxx function annotations
+	Dupok           bool   // duplicate definitions ok
+	Wrapper         bool   // is method wrapper
+	Needctxt        bool   // function uses context register (has closure variables)
+	ReflectMethod   bool   // function calls reflect.Type.Method or MethodByName
+	IsHiddenClosure bool
 }
 
 type Op uint8